EMRFD Chapter 5 Errata.

25Oct06

p5.7, left column, 3 lines up from bottom:   replace "extracted form" with "extracted from"   (9Dec03)

P5.7, Fig 5.17 caption.    Add sentences: “The circuit in C offers good suppression but poor gain. See text.” (2June04)    

p5.7, middle column.   Replace the two paragraphs beginning 0.4 inches down from text top extending to 2.0
inches down from text top with:
"Although suppression has been improved in the circuit of Fig 5.17 C, the topology has canceled the desired
IF output.   The designer/builder must exercise care to guarantee that the addition of balance will not
eliminate the mixing action. "    (2June04)          

p5.7, middle column, 2.1 inches down from text top.  Replace "A variation of the ..." with "A working
variation of the ....."      (2June04)       

p5.11, Fig 5.26, caption:    replace Phillips with Philips.  (This is an error that must surely be present elsewhere. Our apologies to Philips!)  4 May 04  

p5.12,  1st col. second line from top.  Replace "to measured DSB" with  "to measure DSB"      (3Dec03)

p5.17, left column, top of text:  replace "there also be" with "there can also be"    (9Dec03)

p5.18, Fig 5.46 and related discussion:   HC series flip-flops are used in several places throughout EMRFD as frequency dividers to generate square waves that then provide harmonic outputs.    In this discussion we used some really old data suggesting that the output impedance of a CMOS part was around 1K.   That was the end resistance used for filter design.   We recently did some measurements with a HC inverter where a variety of loads were placed on the part.   I measured an output R of 39 Ohms for a single gate.    This drastic difference means that the bandpass filter will have different components and should be redesigned accordingly.   There is no need to change any of the example circuits, for they were all checked with a spectrum analyzer when they were constructed.
     There can be a problem with this low impedance:  When we see a low value, we might be tempted to think that we can do an impedance match to this value and extract a lot of power.    That is probably not true, for there could be stability problems.  Heavily loading the HC output could cause high currents to flow internally in the IC, causing it to exceed power ratings.  A heat sink would then be required.     Loading will usually be light when using the chips for frequency multipliers, for the usual bandpass filter will attach to the IC with a small series capacitor.   This will present a low impedance at the harmonic, but a relatively high Z at the fundamental.    The IC will not be heavily loaded by such a circuit.    An ideal way to design might be to place a 220 Ohm resistor in series with the output.   The composite output impedance would then be about 250 Ohms.  If this value is used for filter design, the result would be worst case 500 Ohm load on the IC which should not cause problems.     (25Oct06)        

p5.21. right column, 2.1 inches down from text top.  Change subtly to subtlety.    (8 July 03)

p5.21.  Reference 8.   Chris Trask informs us that he did not write this early data sheet for the NE-602.  The data sheet in my files has no listed author, but I'm pretty sure it was Bob Zavrel, W7SX, for he did much of the early Signetics applications work on that part. (24Feb03)